Water-cooled transformer



H. O. STEPHENS;

WATER 000m) TRANSFORMER.

APPLICATION FlLED MAR. 25, I919.

Patented Oct. 18, 1921.v

2 SHIEETSSHEET x.

Inventor: Howard epheTlS M- H is ALT, OTTIQH H. O. STEPHENS. WATER COOLERD TRANSFORMER.

APPLICATION men MAR. 25. 1919.

Patented 0ct.'18, 1921. 24 Z SHEETSSHEET 2.

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1T1veT |LoT"2 Hovxjvarol Stephens, by His ILL ornes UNITED STATES PATENT OFFICE.

nowm o. smrnmvs, or rrr'rsrmnn, MASSACHUSETTS, assrenoa "ro GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

WATER-000L131) TRANSFORMER.

To all whom it may concern: Be it known that I, HOWARD O. STEPHENS,

a citizen ofthe United States, residin at Pittsfield, in the county of Berkshire, tate of Massachusetts, have invented certain new and useful Improvements in Water-Cooled Transformers, of which the following is a specification.

My invention relates to stationary induction apparatus, such as transformers and the like and has for its object the provision for an improved construction therefor which is rugged, cheap and economicaL. More specifically my invention relates to transformer and the like which utilize a minimum of material and yet must deliver large currents so that it is convenient and desirable to mount them on the machine served.

by such electrical apparatus. My invention is thus particularly adapted to meet the requirements for transformers used on welding machines.

In machines c onsuming large currents,

such as welding machines where the current often has a'magnitude in the neighborhood of 50,000 amperes, the losses in the leads alone preclude the use of transformers situated at a distance from the machine. The transformer must therefore be light and O0- cupy as little space as. possible especially when the machine itselfis portable.

In meeting .these requirements in space and materials the problem of cooling becomes one of some difficulty of solution; since the permissible space occupied excludes cooling by a circulating medium such as oil. The clearances between turns also become so small that cooling by the circulation of air is impractical, and the core itself prevents cooling by radiation from being effectual over a large windings.

In carrying my invention into effect I have, however, by a novel arrangement of parts providedadequate cooling utilizing both the principles of convection and of conduction Without materially increasing the space originally occupied by the windings themselves. This I have accomplishedby forming the electrical conductors, particularly those in the low voltage winding, in

' a manner adapted to convey a fluid cooling medium (water for instance) along an edge Specification of Letters- Patent.

proportion of the thereof whereby the heat in the other parts of the conductor is rapidly conveyed away. Fora more. complete understanding of the nature and objects of my invention reference.

, Patented Oct. 18, 1921. Application filed March 25, 1919. Serial No. 285,043

while Fig. 4 is a perspective view of one of I the secondary coils,

Referring now to the drawings, 10 denotes a laminated core of magnetic material having three legs 11, 12 and 13, as clearly shown in Fig. 3.

The central leg 12 has an insulating covering 14 and is surrounded by the windings.

The high voltage winding, which iifwelding service is connected as the primary, comprises a coiled conducting tube 15; each layer being shown as having six turns. The leads for this winding comprise the tubular connections shown at 16 and 17 to which the cooling circulating medium, water, is admitted from some non-conductmg tubing such as rubber hose (not shown).

. The layers of this high voltage winding 15,

wliich are shown for the transformer illustrated 1n Fig. 2 as six in number, are spaced apart sufficiently tohave a layer of the low voltage or secondary winding 20 inserted The tubes 21 for the seven conductors 20 preferably I These secondary layers 20, as shown in. Fig. 4, comprise one turn each and may with K uch as water,

\ parts.

mary.

. over the yoke "denoted 20 in Fig. 4.

projecting slitted porers 25 is a narrow The edges of conductors 20 which contain tubes 21 are formed so as to project over and beyond the tubular primary winding 15,

which is interleaved between conductors 20. In this way the vertical space occupied by the two windings is a minimum, since by this arrangement the tube 21 are not superposed upon the tubular windings 15, but occupy a space of their own to one side of the pri- The primary and secondary are preferably bare although a coating of insulatin material such as enamel will' doubtless at times be expedient. To insulate the primary and secondary apart, I employ an insulating covering such as sheet asbestos for this duty which Is made to envelop the secondary and is formed out of sheet insulating material in the following manner: A strip is cut from a sheet of stock and folded once in the form of a U-member 25. This insulating U-member is slipped over the secondary from the inner edge so that it is not unduly distended at its fold by the tube 21'. I

This U-member 25 is out along the fold for a little distance as shown at 26 in Fig. 3 in order to provide a portion projecting portion of secondary turn,

Between the two tions 26 of the U-memb strip of the yoke 20' exposed but for a small 27 that is made from a piece of the sheet stock, which is slipped over "the conductor 20 at this point, preferably again from the inside edge.

The secondary conductors 20 are connected parallel as shown for delivering large current. For this purpose the end portions 28 are bent down so as to'be united together to which would yet be insulating U-member form the terminals 29.

The core is shown as held together by the usual core clamps 30 which may be provided with suitable brackets 31- for mounting the apparatus. I

The windows in the core are made only slightly wider to accommodate the tube 21 than they would be were no such tube employed. By reason of the tube 21 being on the outside edge rather than on the inside edge, a shorter mean turn of conductor is used than would have been the case were the alternate construction used; which construction results in reduced copper losses.

It is also seen that the primary and secondary are assembled snugly together in a manner, without spacing, which permits sufficient cooling in spite of the large currents employed. 7

It is also apparent that the cooling of conductors 20 along one edge, creates along this edge a zone of relatively low temperature compared with the rest of the conductor when traversed by current, to which zone the he'at in the other parts of the conductor flows due to the fairly steep temperature gradient which is in this manner created across the conductor.

In operation the circulating fluid is fed to the pipe connections of the primary and secondary through non-conducting tubing leading the fluid from any convenient head of pressure. This fluid is generally made to flow continuously therethrough, although this is preferable, it is'not necessary.

Having now described what is at present the best means known to me for carrying out an embodiment of my invention, I would have it understood that such means are merely illustrative and that I do not mean to be limited thereby to the exact details shown nor in the choice of recognized equivalents except as defined in my claims hereunto appended.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In an electric apparatus, the combination with a core, of a winding supported thereon, and means for circulating a cooling medium through a portion of said Winding to cool it by convection, the remaining portion being cooled by conduction.

2. In an electric apparatus, the combination with a core, of a winding supported thereon comprising means for circulating a cooling medium through a portion of each of certain predetermined turns, the balance of each of said turns being arranged to conduct heat to said portion.

3. In an electric apparatus, the combination with a core, of a winding supported thereon comprising a single turn per layer, each turn having a tubular formation traversing a portion thereof, and means for circulati'ng a cooling medium through said formation to cool such portion of said turns by convection, the remaining portion being cooled by conduction.

4. In an electric apparatus, the combination with a core, of a winding supported thereon comprising single turns per layer, each turn having an edge provided with a tubular formation connected with the formations on adjacent turns, and means for circuletting a cooling medium in said formations.

5. In a transformer, the combination with a core, of interleaved layers of high and low voltage windings, and means secured along the edges of the low voltage winding whereby the edges of said low voltage winding are cooled by convection.

6. In a transformer or the like, the combination with a core,- of interleaved layers of high and low voltage windings, and tubular means for conveying a cooling fluid about and in contact with edges of said low voltage layers.

7. In a transformer or the like, the combination with a core, of interleaved layers of highand low voltage windings, and piping connections for a cooling fluid formed about the edges of said low voltage layers and ar ranged in thermally conducting relation therewith.

8. In a transformer or the like, the combi nation with a core, of interleaved layers of high and low voltage windings, and a pipe adapted to convey a cooling fluid secured in thermal conductivity with one edge, of each low voltage layer, the pipes of all the layers being connected to convey the cooling fluid in succession therethrough.

In witness whereof, I have hereunto set my hand this 19th day of March, 1919.

HOWARD O. STEPHENS. 

